The main aim of the current study was to develop and validate the Self-Esteem Measure for Prisoners (SEM-P), composed of personal and prison self-esteem, among a systematically selected sample of prisoners (N = 1,794). Confirmatory factor analyses revealed that the SEM-P was best captured with the bifactor conceptualization reflecting two grouping factors (personal and prison self-esteem) and one general factor. Although factor loadings were stronger for the general factor, the two grouping factors evidenced good differential predictive validity. The SEM-P is a reliable and valid measure of self-esteem among inmates because it considers the importance of prison culture for self-evaluations.